Leaking Rotors

I am in the process of switching out old Toro 500 series rotors with new super 800 rotors on an existing system, 19 total on 6 zones ( no more than four rotors per zone ). After changing and testing each rotor I have a problem in two of the zones with the new rotors one in each zone leaking water and not popping up. I spoke to Toro and they told to turn on the zone with the problem, manualy pull up the head and then gently step on the head and pump it up and down four times and this should fix the problem. I did this but it did not fix the problem, could I have a bad rotors? any suggestions would be appreciated